A method for rearing and/or increasing the activity of at least one population of a predator mite species of the family Phytoseiidae comprising the steps: providing at least one rearing population of a predator mite species of the family Phytoseiidae and a first food source for this predator mite species, wherein the rearing population of the predator mite species and the first food source are both located in a common housing, which has at least one opening which allows individuals of the predator mite species to leave the common housing, providing a second food source for the predator mite species, wherein the second food source comprises at least one population of a mite species belonging to the Astigmata, arranging the common housing in or on a plant, and placing the second food source in or on the same or a different plant outside the common housing and preferably spaced apart with respect to the common housing.
